Ultrasonic recognition module, driving method thereof, and display device

ABSTRACT

An ultrasonic recognition module, a driving method thereof, and a display device. Multiple receiving electrodes are divided into multiple receiving groups. Pulse signal input ends of driving circuits corresponding to the receiving electrodes in the same receiving group are electrically connected to a same pulse signal input line, and pulse signal input ends of driving circuits corresponding to the receiving electrodes in the different receiving groups are electrically connected to different pulse signal input lines.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Chinese Patent Application No.201910772744.8, filed on Aug. 21, 2019, which is hereby incorporated byreference in its entirety.

FIELD

The present disclosure relates to the technical field of display, inparticular to an ultrasonic recognition module, a driving methodthereof, and a display device.

BACKGROUND

With continuous development of science and technologies, a fingerprintrecognition technology has gradually been applied to people's dailylife. In the fingerprint recognition technology, identification can beperformed by comparing detailed feature points of different fingerprintsto implement a function of identity identification. Generally, thefingerprint recognition technology can include an optical fingerprintrecognition technology, a silicon chip fingerprint recognitiontechnology, and an ultrasonic fingerprint recognition technology.

Currently, the ultrasonic fingerprint recognition technology is apopular research direction of major manufacturers. An ultrasonicfingerprint recognition structure is mainly a three-layer laminatedstructure, including a driving electrode, a receiving electrode, and apiezoelectric layer located between the two. When a driving voltage isapplied to the driving electrode and the receiving electrode, thepiezoelectric layer is excited by the voltage to generate an inversepiezoelectric effect and transmit a first ultrasonic wave to theoutside. After the first ultrasonic wave contacts a finger, a secondultrasonic wave is reflected by the finger.

Because the fingerprint includes valleys and ridges, there is variancein vibration intensity of the second ultrasonic wave reflected by thefingerprint back to the piezoelectric layer. In this case, when a fixedvoltage is applied to the driving electrode, the piezoelectric layer canconvert the second ultrasonic wave into a voltage signal. The voltagesignal is transmitted to the fingerprint recognition module by thereceiving electrode, and positions of the valleys and the ridges in thefingerprint are determined according to the voltage signal.

SUMMARY

An embodiment of the present disclosure provides an ultrasonicrecognition module, including: a plurality of receiving electrodesarranged in an array and a plurality of driving circuits electricallyconnected to the plurality of receiving electrodes in a one-to-onecorrespondence mode, wherein the plurality of receiving electrodes aredivided into a plurality of receiving groups, the plurality of drivingcircuits respectively includes a pulse signal input end, pulse signalinput ends of the driving circuits corresponding to the receivingelectrodes in the same receiving group are electrically connected to asame pulse signal input line, and the pulse signal input ends of thedriving circuits corresponding to the receiving electrodes in thedifferent receiving groups are electrically connected to different pulsesignal input lines.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, thereceiving electrodes in a same row are located in the same receivinggroup, and the receiving electrodes in different rows are located in thedifferent receiving groups.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, thereceiving electrodes in a same row are located in the same receivinggroup, and the receiving electrodes in different rows are located in thedifferent receiving groups.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, theplurality of driving circuits respectively include a diode, a firstswitch transistor, a second switch transistor, and a third switchtransistor; wherein,

a first end of the diode is electrically connected to a receivingelectrode, and a second end of the diode is electrically connected tothe pulse signal input end;

a gates of the first switch transistor is electrically connected to areset signal end, a first pole of the first switch transistor iselectrically connected to the receiving electrode, and a second pole ofthe first switch transistor is electrically connected to the pulsesignal input end; and

a gate of the second switch transistor is electrically connected to thereceiving electrode, a first pole of the second switch transistor iselectrically connected to a power supply end, and a second pole of thesecond switch transistor is connected to a first pole of the thirdswitch transistor, a gate of the third switch transistor is electricallyconnected to a scanning signal end, and a second pole of the thirdswitch transistor is electrically connected to a signal reading end.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, the drivingcircuits respectively include a storage capacitor, a first switchtransistor, a second switch transistor, and a third switch transistor;wherein,

a first end of the storage capacitor is electrically connected to thereceiving electrode, and a second ends of the storage capacitor isgrounded;

a gate of the first switch transistor is electrically connected to areset signal end, a first pole of the first switch transistor iselectrically connected to the receiving electrode, and a second pole ofthe first switch transistor is electrically connected to the pulsesignal input end; and

a gate of the second switch transistor is electrically connected to thereceiving electrode, a first pole of the second switch transistor iselectrically connected to a power supply end, a second pole of thesecond switch transistor is electrically connected to a first pole ofthe third switch transistor, a gate of the third switch transistor iselectrically connected to a scanning signal end, and a second pole ofthe third switch transistor is electrically connected to a signalreading end.

Optionally, in specific implementation, the ultrasonic recognitionmodule provided by the embodiment of the present disclosure furtherincludes: a driving electrode disposed opposite to a film layer wherethe plurality of receiving electrodes are located, and a piezoelectriclayer located between the driving electrode and the film layer where theplurality of receiving electrodes are located, wherein the drivingelectrode and the piezoelectric layer are formed over an entire surface.

Correspondingly, an embodiment of the present disclosure furtherprovides a display device, including the ultrasonic recognition moduleprovided by the embodiment of the present disclosure.

Correspondingly, an embodiment of the present disclosure furtherprovides a driving method of the ultrasonic recognition module providedby the embodiment of the present disclosure, including:

providing multiple detection points for by the ultrasonic recognitionmodule, wherein each of the detection points corresponds to theplurality of receiving groups, and one receiving group corresponds toonly one detection point; and

applying pulse signals to pulse signal input ends of the plurality ofreceiving groups corresponding to a same detection point by using thepulse signal input lines, wherein time points for loading the pulsesignals by receiving groups that are at a same distance from thedetection point are same, and time points for loading the pulse signalsby receiving groups that are closer to the detection point are laterthan time points for loading the pulse signals by receiving groups thatare far from the detection point.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, the receiving electrodes located in a same row are areceiving group, or the receiving electrodes located in a same columnare a receiving group.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, simultaneously performing a ultrasonic detection ondetection points corresponding to the receiving groups which do notspatially cross.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, sequentially perform a ultrasonic detection is on detectionpoints corresponding to the receiving groups which spatially cross.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, the sequentially performing the ultrasonic detection on thedetection points, comprises:

receiving electrodes of the plurality of receiving groups correspondingto other detection points are in a floating state in response to thatperforming the ultrasonic detection one detection point.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, every two adjacent receiving groups correspond to thedifferent detection points, and the receiving groups corresponding tothe different detection points are alternately arranged.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, each detection point corresponds to an odd number ofreceiving groups, and the receiving group in the center location of theodd number of receiving groups is a first receiving group, the receivinggroups on both sides of the first receiving group are second receivinggroups, all the second receiving groups are symmetrically arranged alongthe first receiving group, and the detection point is located rightabove the first receiving group.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of transmitting ultrasonic waves by anultrasonic recognition module;

FIG. 2 is a schematic diagram of receiving ultrasonic waves by anultrasonic recognition module;

FIG. 3 is a schematic diagram of performing fingerprint recognition byan ultrasonic recognition module;

FIG. 4 is a schematic structural diagram of an ultrasonic recognitionmodule;

FIG. 5 is a first schematic structural top view of an ultrasonicrecognition module according to an embodiment of the present disclosure;

FIG. 6 is a second schematic structural top view of an ultrasonicrecognition module according to an embodiment of the present disclosure;

FIG. 7 is a first schematic structural diagram of a driving circuitaccording to an embodiment of the present disclosure;

FIG. 8 is a second schematic structural diagram of a driving circuitaccording to an embodiment of the present disclosure;

FIG. 9 is a schematic flowchart of a driving method of an ultrasonicrecognition module according to an embodiment of the present disclosure;

FIG. 10 is a first principle diagram of a driving method of anultrasonic recognition module according to an embodiment of the presentdisclosure;

FIG. 11 is a second principle diagram of a driving method of anultrasonic recognition module according to an embodiment of the presentdisclosure;

FIG. 12 is a third principle diagram of a driving method of anultrasonic recognition module according to an embodiment of the presentdisclosure;

FIG. 13 is a fourth principle diagram of a driving method of anultrasonic recognition module according to an embodiment of the presentdisclosure;

FIG. 14 is a fifth principle diagram of a driving method of anultrasonic recognition module according to an embodiment of the presentdisclosure;

FIG. 15 is a sixth principle diagram of a driving method of anultrasonic recognition module according to an embodiment of the presentdisclosure;

FIG. 16 is a diagram of durations of ultrasonic waves of the drivingmethod of the ultrasonic recognition module shown in FIG. 10 and FIG.11;

FIG. 17 is a diagram of durations of ultrasonic waves of the drivingmethod of the ultrasonic recognition module shown in FIG. 14 and FIG.15;

FIG. 18 is a timing diagram of a driving method of an ultrasonicrecognition module according to an embodiment of the present disclosure;and

FIG. 19 is a schematic structural diagram of a display device accordingto an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To make the objectives, technical solutions and advantages of thepresent disclosure clearer, specific implementations of an ultrasonicrecognition module, a driving method thereof, and a display deviceprovided by the embodiments of the present disclosure will be describedin detail below with reference to the accompanying drawings.

The thickness and shape of each layer of film in the drawings do notreflect a true proportion of the ultrasonic recognition module, and theobjective is only to schematically illustrate the content of the presentdisclosure.

FIG. 1 is a schematic diagram of transmitting ultrasonic waves by anultrasonic recognition module. FIG. 2 is a schematic diagram ofreceiving ultrasonic waves by an ultrasonic recognition module. FIG. 3is a schematic diagram of performing fingerprint recognition by anultrasonic recognition module. FIG. 4 is a schematic structural diagramof an ultrasonic recognition module.

As shown in FIG. 1, the ultrasonic recognition module includes anultrasonic sensor 10. The ultrasonic sensor 10 includes an upperelectrode 11, a lower electrode 12, and a piezoelectric layer 13 locatedbetween the upper electrode 11 and the lower electrode 12. Thepiezoelectric layer 13 is made of piezoelectric materials, and can beexcited by a voltage to generate a reverse piezoelectric effect. When analternating voltage (an AC voltage) is inputted to the upper electrode11 and the lower electrode 12 (for example, the upper electrode 11 isgrounded, and an AC square wave is applied to the lower electrode 12),due to the inverse piezoelectric effect, the piezoelectric layer 13 maybe deformed or drive film layers above and below the piezoelectric layer13 to vibrate together, so that ultrasonic waves can be generated andtransmitted outward. It should be noted that when a cavity (such as anair cavity) is formed in the side, away from the piezoelectric layer 13,of the upper electrode 11 or the side, away from the piezoelectric layer13, of the lower electrode 12, the ultrasonic waves transmitted by theultrasonic sensor can be strengthened, so that the ultrasonic waves canbe better transmitted.

As shown in FIG. 2, the ultrasonic waves transmitted by the ultrasonicsensor 10 are reflected by a fingerprint 100, and the reflectedultrasonic waves are converted into an alternating voltage in thepiezoelectric layer 13. In this case, the upper electrode 11 isgrounded, and the lower electrode 12 can be used as a receivingelectrode to receive the alternating voltage generated by thepiezoelectric layer 13. The fingerprint 100 includes valleys 110 andridges 120, and they have different reflection capabilities for theultrasonic waves (the valleys 110 have a stronger reflection capabilityfor the ultrasonic waves). Therefore, the intensity of the ultrasonicwaves reflected by the valleys 110 is different from the intensity ofthe ultrasonic waves reflected by the ridges 120. Therefore, whether theultrasonic waves are reflected by the valleys or by the ridges can bejudged by using the alternating voltage received by the receivingelectrode.

As shown in FIG. 3, the ultrasonic recognition module includes an upperelectrode 11, multiple lower electrodes 12, a piezoelectric layer 13located between the upper electrode 1 and the multiple lower electrodes12, a substrate 20 located on the side, away from the piezoelectriclayer 13, of the upper electrode 11, and a protective layer 30 locatedon the side, away from the piezoelectric layer 13, of the multiple lowerelectrodes 12. The ultrasonic sensor 10 made of the lower electrode 12,the piezoelectric layer 13 and the multiple upper electrodes 11 cantransmit the ultrasonic waves and can also receive the ultrasonic waves,that is, the ultrasonic sensor 10 functions as both an ultrasonictransmitting sensor and an ultrasonic receiving sensor. When thefingerprint is in contact with the substrate 20, the ultrasonic wavestransmitted by the ultrasonic sensor 10 are reflected by the fingerprint100, and the reflected ultrasonic waves are converted into analternating voltage in the piezoelectric layer 13. In this case, theupper electrode 11 is grounded, and the multiple lower electrodes 12 canbe used as receiving electrodes, so that the alternating voltagegenerated by the piezoelectric layer 13 can be received at differentpositions. The fingerprint 100 includes valleys 110 and ridges 120, andthey have different reflection capabilities for the ultrasonic waves(the valleys 110 have a stronger reflection capability for theultrasonic waves). Therefore, the intensity of the ultrasonic wavesreflected by the valleys 110 is different from the intensity of theultrasonic waves reflected by the ridges 120. Therefore, the positioninformation of the valleys and the ridges in the fingerprint 100 can beobtained by using the alternating voltages received by the multiplelower electrodes 12, so that fingerprint recognition can be implemented.

As shown in FIG. 4, the upper electrode 11, the lower electrodes 12 andthe piezoelectric layer 13 may all be manufactured on the same side of athin film transistor substrate 31. The ultrasonic recognition modulefurther includes: a bias resistor 40 and a binding pad 50. The biasresistor 40 can be used for calibrating a voltage, and the binding pad50 can be used for binding an external circuit.

In the research, the inventor of the present disclosure finds that inthe process of transmitting ultrasonic waves by the ultrasonicrecognition module, when the entire ultrasonic recognition modulesimultaneously performs transmitting, performance of fingerprintrecognition is poor.

In view of this, an embodiment of the present disclosure provides anultrasonic recognition module. As shown in FIG. 5 and FIG. 6, FIG. 5 andFIG. 6 are respectively schematic structural top views of the ultrasonicrecognition module according to an embodiment of the present disclosure.The ultrasonic recognition module includes multiple receiving electrodes121 arranged in an array, and multiple driving circuits (not shown inFIG. 5 and FIG. 6) electrically connected to the receiving electrodes121 in one-to-one correspondence. The multiple receiving electrodes 121are divided into multiple receiving groups A. As shown in FIG. 5, eachrow of receiving electrodes 121 is a receiving group A. As shown in FIG.6, each column of receiving electrodes 121 is a receiving group A. Asshown in FIG. 7 and FIG. 8, FIG. 7 and FIG. 8 are respectively schematicdiagrams of two types of circuit structures of the driving circuits. Thedriving circuits 300 include pulse signal input ends (Vres and Vbias inFIG. 7, and Dbias in FIG. 8). Vres and Vbias input a same pulse signal.The pulse signal input ends, such as Vres and Vbias, of the drivingcircuits 300 corresponding to the receiving electrodes 121 in the samereceiving group A are electrically connected to a same pulse signalinput line (not shown in FIG. 5 and FIG. 6), and the pulse signal inputends, such as Vres and Vbia, of the driving circuits 300 correspondingto the receiving electrodes 121 in the different receiving groups A areelectrically connected to different pulse signal input lines.

In the ultrasonic recognition module provided by the embodiment of thepresent disclosure, the receiving electrodes are divided into themultiple receiving groups. The pulse signal input ends of the drivingcircuits corresponding to the receiving electrodes in the same receivinggroup are electrically connected to the same pulse signal input line,and the pulse signal input ends of the driving circuits corresponding tothe receiving electrodes in the different receiving groups areelectrically connected to the different pulse signal input lines.Focusing of the ultrasonic waves can be implemented by using theultrasonic recognition module. On the one hand, the intensity or energyof the transmitted ultrasonic waves in a detection point area can beimproved, so that performance of fingerprint recognition is improved. Onthe other hand, the transmitted ultrasonic waves can have betterdirectivity, so that crosstalk between valleys and ridges of afingerprint can be reduced, and the performance of fingerprintrecognition can be further improved.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, as shown inFIG. 5, the receiving electrodes 121 in the same row are located in thesame receiving group A, and the receiving electrodes 121 in thedifferent rows are located in the different receiving groups A.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, as shown inFIG. 6, the receiving electrodes 121 in the same column are located inthe same receiving group A, and the receiving electrodes 121 in thedifferent columns are located in the different receiving groups A.

It should be noted that FIG. 5 and FIG. 6 are merely two possibleembodiments for grouping the receiving electrodes enumerated in thepresent disclosure. Certainly, in specific implementation, there may beother types of grouping embodiments that are not enumerated herein.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, as shown inFIG. 7, the driving circuit 300 includes a diode L, a first switchtransistor T1, a second switch transistor T2, and a third switchtransistor T3.

A first end of the diode L is electrically connected to a receivingelectrode 121, and a second end of the diode L is electrically connectedto a pulse signal input end Vbias.

A gate of the first switch transistor T1 is electrically connected to areset signal end Rest, a first pole of the first switch transistor T1 iselectrically connected to the receiving electrode 121, and a second poleof the first switch transistor T1 is electrically connected to a pulsesignal input end Vres.

A gate of the second switch transistor T2 is electrically connected tothe receiving electrode 121, a first pole of the second switchtransistor T2 is electrically connected to a power supply end VDD, and asecond pole of the second switch transistor T2 is electrically connectedto a first pole of the third switch transistor T3. A gate of the thirdswitch transistor T3 is electrically connected to a scanning signal endGate, and a second pole of the third switch transistor T3 iselectrically connected to a signal reading end Read.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, as shown inFIG. 8, the driving circuit 300 includes a storage capacitor C, a firstswitch transistor T1, a second switch transistor T2, and a third switchtransistor T3.

A first end of the storage capacitor C is electrically connected to areceiving electrode 121, and a second end of the storage capacitor C isgrounded.

A gate of the first switch transistor T1 is electrically connected to areset signal end Rest, a first pole of the first switch transistor T1 iselectrically connected to the receiving electrode 121, and a second poleof the first switch transistor T1 is electrically connected to a pulsesignal input end Dbias.

A gate of the second switch transistor T2 is electrically connected tothe receiving electrode 121, a first pole of the second switchtransistor T2 is electrically connected to a power supply end VDD, and asecond pole of the second switch transistor T2 is electrically connectedto a first pole of the third switch transistor T3. A gate of the thirdswitch transistor T3 is electrically connected to a scanning signal endGate, and a second pole of the third switch transistor T3 iselectrically connected to a signal reading end Read.

Optionally, in specific implementation, in the ultrasonic recognitionmodule provided by the embodiment of the present disclosure, as shown inFIG. 5 and FIG. 6, the ultrasonic recognition module further includes: adriving electrode 11 disposed opposite to a film layer where thereceiving electrodes 121 are located, a piezoelectric layer 13 betweenthe driving electrode 11 and the film layer where the receivingelectrodes 121 are located. The driving electrode 11 and thepiezoelectric layer 13 are formed over an entire surface.

Optionally, to make the ultrasonic recognition module have higherreceiving sensitivity to the ultrasonic waves, the piezoelectric layer13 is generally made of a piezoelectric material, such as PVDF(polyvinylidene fluoride), with a high piezoelectric constant.

Based on the same inventive concept, an embodiment of the presentdisclosure provides a driving method of an ultrasonic recognitionmodule. As shown in FIG. 9, the method includes the following steps:

S901, providing multiple detection points by the ultrasonic recognitionmodule. Each detection point corresponds to multiple receiving groups,and one receiving group corresponds to only one detection point.Specifically, as shown in FIG. 10 and FIG. 11, FIG. 10 and FIG. 11 arerespectively schematic principle diagrams of ultrasonic detectioncorresponding to each detection point. The ultrasonic recognition moduleis provided with multiple detection points 200. Each detection point 200corresponds to the multiple receiving groups A, and one receiving groupA corresponds to only one detection point 200; and S902, applying pulsesignals to pulse signal input ends of the multiple receiving groupscorresponding to the same detection point by using the pulse signalinput lines. Time points for loading the pulse signals by the receivinggroups that are at the same distance from the detection point are thesame, and time points for loading the pulse signals by the receivinggroups that are close to the detection point are later than time pointsfor loading the pulse signals by the receiving groups that are far fromthe detection point.

In the driving method of the ultrasonic recognition module provided bythe embodiment of the present disclosure, the multiple receivingelectrodes are divided into the multiple receiving groups. The pulsesignal input ends of the driving circuits corresponding to the receivingelectrodes in the same receiving group are electrically connected to thesame pulse signal input line, and the pulse signal input ends of thedriving circuits corresponding to the receiving electrodes in thedifferent receiving groups are electrically connected to the differentpulse signal input lines. The pulse signals are applied to the pulsesignal input ends of the multiple receiving groups corresponding to thesame detection point by using the pulse signal input lines; the timepoints for loading the pulse signals by the receiving groups that are atthe same distance from the detection point are the same, and the timepoints for loading the pulse signals by the receiving groups that areclose to the detection point are later than time points for loading thepulse signals by the receiving groups that are far from the detectionpoint. In the driving method of the ultrasonic recognition moduleprovided by the embodiment of the present disclosure, the receivingelectrodes are grouped, and the multiple receiving groups correspondingto each detection point determine the time point of inputting the pulsesignals according to the distance from the detection point, so thatfocusing of ultrasonic waves can be implemented. On the one hand, theintensity or energy of the transmitted ultrasonic waves in a detectionpoint area can be improved, so that performance of fingerprintrecognition is improved. On the other hand, the transmitted ultrasonicwaves can have better directivity, so that crosstalk between valleys andridges of a fingerprint can be reduced, and the performance offingerprint recognition can be further improved.

It should be noted that the detection points in the embodiment of thepresent disclosure refers to touch positions when a finger touches theultrasonic recognition module.

Further, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, as shown in FIG. 5, the receiving electrodes 121 located inthe same row are the receiving group A, or as shown in FIG. 6, thereceiving electrodes 121 in the same column are the receiving group A.

Optionally, the driving electrode 11 provided in the embodiment of thepresent disclosure is arranged on an entire surface, and the multiplereceiving electrodes 121 are independently disposed; therefore, onlywhen corresponding voltages are applied to both the driving electrode 11and the receiving electrodes 121, the piezoelectric layer 13 can bedeformed to transmit ultrasonic waves. The six receiving groups A areused as an example in schematic principle diagrams of ultrasonicdetection shown in FIG. 10 and FIG. 11. Each receiving group Acorresponds to one row or column of receiving electrodes 121. Onedetection point 200 corresponds to the three receiving groups A. All thedriving electrodes 11, the piezoelectric layer 13 corresponding to thedriving electrodes 11, and the receiving groups A overlapped with thedriving electrodes 11 constitute an ultrasonic transmitting element. Allthe receiving electrodes 121, the piezoelectric layer 13 correspondingto the receiving electrode 121, and the driving electrode 11 overlappedwith the receiving electrodes 121 constitute an ultrasonic receivingelement. When the ultrasonic recognition module performs fingerprintrecognition, the receiving electrodes 121 can be grounded, and then analternating voltage is applied to the driving electrode 11. Due to theinverse piezoelectric effect, the piezoelectric layer 13 correspondingto the driving electrode can be deformed or drive film layers on theupper part and the lower part of the piezoelectric layer 13 to vibratetogether, so that ultrasonic waves can be generated and transmittedoutward. The ultrasonic recognition module includes the multiplereceiving electrodes 121 arranged in the array, the multiple receivingelectrodes 121 are divided into the multiple receiving groups A, and thereceiving electrodes 121 in each receiving group A are electricallyconnected to the same pulse signal input line. Therefore, each receivinggroup can constitute one ultrasonic transmitting element, that is, themultiple receiving groups can constitute multiple ultrasonictransmitting elements, so that focusing of the ultrasonic waves can beimplemented by separately driving the multiple groups of receivingelectrodes. On the one hand, the intensity or energy of the transmittedultrasonic waves in the detection point area can be improved, so thatthe performance of fingerprint recognition is improved. On the otherhand, the transmitted ultrasonic waves can have the better directivity,so that crosstalk between the valleys and the ridges of the fingerprintcan be reduced, and performance of fingerprint recognition can befurther improved. When the transmitted ultrasonic waves are reflectedback to the ultrasonic recognition module by the fingerprint, themultiple ultrasonic receiving elements corresponding to the multiplereceiving electrodes 121 can receive the reflected ultrasonic waves andconvert the ultrasonic signals into electrical signals, so thatfingerprint identification is implemented.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, as shown in FIG. 12, ultrasonic detection is simultaneouslyperformed on the detection points 200 corresponding to the receivinggroups A which do not spatially cross. Because the receiving groups Acorresponding to the detection points 200 do not spatially cross, thedetection points 200 do not affect each other when receiving theultrasonic waves, and ultrasonic detection can be simultaneouslyperformed, so that the recognition time of the entire ultrasonicrecognition module is reduced.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided in the embodiment of the presentdisclosure, as shown in FIG. 13, ultrasonic detection is sequentiallyperformed on the detection points 200 corresponding to the receivinggroups A which spatially cross. For example, ultrasonic detection isfirst performed on the detection point 200 on the left side of FIG. 11,and ultrasonic detection is then performed on the detection point 200 onthe right side. Because the receiving groups A corresponding to thedetection points 200 spatially cross, ultrasonic wave detection needs tobe performed on these detection points 200 in a time division mode toavoid interference when the detection points receive the ultrasonicwaves, so that accuracy of fingerprint detection is improved.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided in the embodiment of the presentdisclosure, as shown in FIG. 13, ultrasonic detection is sequentiallyperformed on the detection points corresponding to the receiving groupsA 200 spatially crossing. Specifics are as follows:

when ultrasonic detection is performed on one detection point 200 (suchas on the left side), the receiving electrodes 121 of the multiplereceiving groups A corresponding to the other detection point 200 (suchas on the right side) are in a floating state. Specifically, the drivingelectrode in the ultrasonic recognition module provided by theembodiment of the present disclosure is an electrode provided on anentire surface, and there are multiple receiving electrodes arranged inthe array. Therefore, when ultrasonic detection is performed on thedetection point 200 on the left side, a voltage only needs to be appliedto the driving electrode and the receiving electrodes of the threereceiving groups A corresponding to the detection point 200 on the leftside, and the time point of inputting a pulse signal to the receivinggroup A (the third receiving group A from the left) that is close to thedetection point 200 is later than the time point of inputting a pulsesignal to the receiving groups A (the first receiving group and fifthreceiving group A from the left) that are far from the detection point200. However, no voltage is applied to the receiving electrodes of thethree receiving groups A corresponding to the detection point 200 on theright side, that is, the receiving electrodes of the three receivinggroups A corresponding to the detection point 200 on the right side arein a floating (Floating) state. After ultrasonic detection on thedetection point 200 on the left side is completed, and no voltage isapplied to the receiving electrodes of the three receiving groups Acorresponding to the detection point 200 on the left side, that is, thereceiving electrodes of the three receiving groups A corresponding tothe detection point 200 on the left side are in a floating (Floating)state, a voltage is applied to the receiving electrodes of the threereceiving groups A corresponding to the detection point 200 on the rightside, and the time point of inputting a pulse signal to the receivinggroup A (the fourth receiving group A from the left) that is close tothe detection point 200 is later than the time point of inputting apulse signal to the receiving groups (the second receiving group and thesixth receiving group A from the left) that are far from the detectionpoint 200, to perform ultrasonic detection on the detection point 200 onthe right side. In this way, ultrasonic detection is sequentiallyperformed on the detection points 200 which spatially cross, so thatinterference does not occur.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, as shown in FIG. 13, every two adjacent receiving groups Acorrespond to the different detection points 200, and the receivinggroup A corresponding to the different detection points 200 arealternatively arranged. Optionally, the first receiving group A from theleft corresponds to the first detection point 200 from the left, thesecond receiving group A from the left corresponds to the seconddetection point 200 from the left, the third receiving group A from theleft corresponds to the first detection point 200 from the left, thefourth receiving group A from the left corresponds to the seconddetection point 200 from the left, the fifth receiving group A from theleft corresponds to the first detection point 200 from the left, and thesixth receiving group from the left A corresponds to the seconddetection point 200 from the left, that is, every two adjacent receivinggroups A correspond to the different detection points 200, and thereceiving groups A corresponding to the different detection points 200are alternately arranged. Certainly, in specific implementation, everyadjacent three receiving groups A can correspond to the same detectionpoint 200, and the receiving groups A corresponding to the detectionpoints 200 do not spatially cross, t the receiving electrodes arrangedin an array are only grouped, all the groups are electrically connectedto the different pulse signal input lines correspondingly, and the timepoint of inputting the pulse signal to the receiving group that is closeto the detection point is later than the time point of inputting a pulsesignal to the receiving group that is far from the detection point.These all belong to the scope of the present disclosure, and are notenumerated herein.

Optionally, in specific implementation, in the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, as shown in FIG. 10 to FIG. 15, each detection point 200corresponds to an odd number of receiving groups A, and the receivinggroup A in the center location of the odd number of receiving groups Ais a first receiving group, the receiving groups A on both sides of thefirst receiving group are second receiving groups, the second receivinggroups are symmetrically arranged along the first receiving group, andthe detection point 200 is located directly above the first receivinggroup. A voltage is applied to the driving electrode, a pulse signal isapplied to the second receiving groups at a first time point, and apulse signal is applied to the first receiving group in a second timepoint. The second time point is later than the first time point becausethe first receiving group is relatively close to the detection point200. Therefore, the design of the present disclosure can implementfocusing of the ultrasonic waves, that is, the intensity or energy ofthe ultrasonic waves directly above the first receiving group isenhanced, so that accuracy of fingerprint recognition is improved.

Optionally, as shown in FIG. 10 and FIG. 11, the time point of inputtingthe pulse signal to the receiving group A that is close to the detectionpoint 200 is later than the time point of inputting the pulse signal tothe receiving group A that is far from the detection point 200.Therefore, a timing diagram of ultrasonic transmission of the receivinggroups A corresponding to the detection points 200 in FIG. 10 and FIG.11 is shown in FIG. 16. Optionally, the ultrasonic transmission timingcorresponding to the first receiving group A (the distance from thedetection point is d2) and the fifth receiving group A (the distancefrom the detection point is d3) from the left in FIG. 10 is ultrasonicwaves d2 and d3 as shown in FIG. 12, and the ultrasonic transmissiontiming corresponding to the third receiving group A from the left (thedistance from the detection point is d1) in FIG. 10 is the ultrasonicwave d1 as shown in in FIG. 12. It can be learned that d1 is transmittedlater than d2 and d3, and d2 and d3 are simultaneously transmitted, sothat the ultrasonic waves are focused directly above the third receivinggroup A. The ultrasonic transmission timing corresponding to the secondreceiving group A (the distance from the detection point is d2) and thesixth receiving group A (the distance from the detection point is d3)from the left in FIG. 11 is ultrasonic waves d2 and d3 as shown in FIG.12, and the ultrasonic transmission timing corresponding to the fourthreceiving group A from the left (the distance from the detection pointis d1) in FIG. 11 is the ultrasonic wave d1 as shown in in FIG. 12. Itcan be learned that d1 is transmitted later than d2 and d3, and d2 andd3 are simultaneously transmitted, but the time of transmitting theultrasonic signal of d1 is shorter than the time of transmitting theultrasonic signals of d2 and d3, so that the ultrasonic waves arefocused directly above the fourth receiving group A.

As shown in FIG. 14 and FIG. 15, another embodiment of ultrasonictransmission is provided. A timing diagram of ultrasonic transmission ofthe receiving groups A corresponding to the detection points 200 in FIG.14 and FIG. 15 is shown in FIG. 17. The time point of transmitting theultrasonic wave by the receiving group A that is close to the detectionpoint is later than the time point of transmitting the ultrasonic waveby the receiving group A that is far from the detection point, butdurations of the ultrasonic signals transmitted by the three receivinggroups are the same.

Optionally, in diagrams of ultrasonic transmission durationcorresponding to FIG. 16 and FIG. 17, focusing of the ultrasonic wavescan be implemented.

FIG. 18 is a timing diagram of a driving method of an ultrasonicrecognition module according to an embodiment of the present disclosure.Specifically, FIG. 18 is a timing diagram of the driving circuit shownin FIG. 7. The detection point 200 and the receiving groups A shown inFIG. 10 are used as an example to explain the principle of focusing ofthe ultrasonic waves. As shown in FIG. 18, three stages: transmitting,sampling and reading are included. Specifically, FIG. 10 is only basedon an example in which the six rows of receiving electrodes A correspondto the two detection points 200. Certainly, in specific implementation,more rows of receiving electrodes and more detection points may beincluded.

The transmitting stage: A driving voltage is applied to the drivingelectrode 11 (shown as Tx in FIG. 18), signals of the reset signal endsRest corresponding to a first row, a third row, and a fifth row are highpotential signals, and all second switch transistors T2 corresponding tothe first row, the third row, and the fifth row are turned on. Thereceiving groups A corresponding to the first row, the third row, andthe fifth row of receiving electrodes 121 correspond to the samedetection point 200, and the distance from the receiving groups Acorresponding to the first row and the fifth row to the detection point200 is greater than the distance from the receiving group Acorresponding to the third row to the detection point 200. Therefore,pulse signals are inputted to the first row and the fifth row ofreceiving electrodes in the receiving groups A by using the pulse signalinput end Vres, so that the voltage is applied to the first row and thefifth row of receiving electrodes in the receiving groups A, to drivethe piezoelectric layer 13 corresponding to the first row and the fifthrow of receiving electrodes to transmit the ultrasonic waves. However, atime point at which a voltage is applied to the receiving electrodes ofthe third row of receiving group A input the voltage later than thevoltage input by the first row and the fifth row of receiving electrodesby using the pulse signal input end Vres, so that the ultrasonic wavesare focused at the detection point 200 located directly above thethird-row receiving group A. In a process of performing ultrasonicdetection on the detection points 200 corresponding to the first row,the third row, and the fifth row of receiving electrodes 121, signals ofreset signal ends Rest corresponding to a second row, a fourth row, anda sixth row are low-potential signals, and all second switch transistorsT2 corresponding to the second row, the fourth row, and the sixth roware cut off, and no voltage is applied to the receiving electrodes 121corresponding to the second row, the fourth row, and the sixth row, sothat the second row, the fourth row, and the sixth row of receivingelectrodes 121 are in a floating state (Floating high impedance state)in the three stages. Although the voltage is applied to the drivingelectrodes corresponding to the second row, the fourth row, and thesixth row, the receiving electrodes corresponding to the second row, thefourth row, and the sixth row are in a floating state. Therefore, thepiezoelectric layer cannot be driven, and ultrasonic waves cannot betransmitted in the second row, the fourth row, and the sixth row.

The sampling stage: Signals of reset signal ends Rest corresponding tothe first row, the third row, and the fifth row are low-potentialsignals, and all second switch transistors T2 corresponding to the firstrow, the third row, and the fifth row are cut off. A pulse signal Vb1 isinputted by a pulse signal input end Vbias, the pulse signal Vb1 ishigher than the pulse signal Vr inputted by Vres during the transmittingstage, and a diode L performs sampling.

The reading stage: Because the detection point 200 is located above thethird-row receiving group A, the ultrasonic signal of the third row isread. For example, a reading instruction signal is applied to a scanningsignal end Gate of the third row, and all third switch transistors T3are turned on, to read the ultrasonic signal.

Therefore, ultrasonic detection of the detection points corresponding tothe first row, the third row, and the fifth row of receiving electrodesis implemented by using the above three stages. After ultrasonicdetection of the detection points corresponding to the first row, thethird row, and the fifth row of receiving electrodes is completed,ultrasonic detection of the detection points corresponding to the secondrow, the fourth row, and the sixth row of receiving electrodes isperformed. As shown in the timing diagram on the right side in FIG. 18,a specific detection principle is the same as the principle ofultrasonic detection of the detection points corresponds to the firstrow, the third row, and the fifth row of receiving electrodes. Detailsare not described in herein.

It should be noted that the timing diagram shown in FIG. 18 is only anexample provided by the embodiment of the present disclosure, and thedriving circuit provided by the embodiment of the present disclosure mayalso be driven by other timing according to actual conditions.

In specific implementation, focusing of the ultrasonic waves can also beimplemented by using the driving circuit shown in FIG. 8. In theembodiment of the present disclosure, focusing of the ultrasonic wavescan further be performed according to the driving circuit shown in FIG.8. Specifically, floating or modulation is performed on one end of thereceiving electrode 121. Specifically, floating is performed on Dbias,and thus an rst switch is turned on. Alternatively, the rst switch isturned on, and thus a waveform the same as Tx is inputted by usingDbias.

Based on the same inventive concept, an embodiment of the presentdisclosure further provides a display device, including any one of theforegoing ultrasonic recognition modules provided by the embodiments ofthe present disclosure. The principle of the display device for solvingthe problem is similar to that of the ultrasonic recognition module.Therefore, implementation of the display device can refer toimplementation of the ultrasonic recognition module. Details are notrepeated herein.

In specific implementation, as shown in FIG. 19, the display devicefurther includes a display module 500, and an area of the display module500 is substantially the same as that of the ultrasonic recognitionmodule 400, so that full-screen fingerprint recognition can beimplemented. In this case, the ultrasonic recognition module can furtherimplement a touch control function, so that there may no need to provideadditional touch devices such as a capacitive touch panel, and costs ofthe display device can be reduced. Certainly, the embodiments of thepresent disclosure include, but are not limited to the above contents.The area of the display module and the area of the ultrasonicrecognition module may not be equal, and the ultrasonic recognitionmodule may be disposed only in a region in which fingerprintidentification is required.

In specific implementation, the display device provided by theembodiment of the present disclosure may be any product or component,such as a mobile phone, a tablet computer, a television, a display, anotebook computer, a digital photo frame, and a navigator, having adisplay function. It should be understood by the person of ordinaryskill in the art that the display device has other essential components.Details are not described herein. This should not be used as alimitation on the present disclosure. For the implementation of thedisplay device, reference may be made to the embodiments of the displaypanel. Details are not repeated herein.

The embodiments of the present disclosure provide the ultrasonicrecognition module, the driving method thereof, and the display device.The multiple receiving electrodes are divided into the multiplereceiving groups. The pulse signal input ends of the driving circuitscorresponding to the receiving electrodes in the same receiving groupare electrically connected to the same pulse signal input line, and thepulse signal input ends of the driving circuits corresponding to thereceiving electrodes in the different receiving groups are electricallyconnected to the different pulse signal input lines. The pulse signalsare applied to the pulse signal input ends of the multiple receivinggroups corresponding to the same detection point by using the pulsesignal input lines; the time points for loading the pulse signals by thereceiving groups that are at the same distance from the detection pointare the same, and the time points for loading the pulse signals by thereceiving groups that are close to the detection point are later thantime points for loading the pulse signals by the receiving groups thatare far from the detection point. In the driving method of theultrasonic recognition module provided by the embodiment of the presentdisclosure, the receiving electrodes are grouped, and the multiplereceiving groups corresponding to each detection point determine thetime point of inputting the pulse signal according to the distance fromthe detection point, so that focusing of the ultrasonic waves can beimplemented. On the one hand, the intensity or energy of the transmittedultrasonic waves in a detection point area can be improved, so thatperformance of fingerprint recognition is improved. On the other hand,the transmitted ultrasonic waves can have better directivity, so thatcrosstalk between valleys and ridges of a fingerprint can be reduced,and the performance of fingerprint recognition can be further improved.

Obviously, a person skilled in the art can make various modificationsand variations to the present disclosure without departing from thespirit and scope of the present disclosure. In this way, if thesemodifications and variations of the present disclosure fall within thescope of the claims of the present disclosure and their equivalenttechnologies, the present disclosure also intends to include thesemodifications and variations.

1. An ultrasonic recognition module, comprising: a plurality ofreceiving electrodes arranged in an array, and a plurality of drivingcircuits electrically connected to the plurality of receiving electrodesin a one-to-one correspondence mode, wherein the plurality of receivingelectrodes are divided into a plurality of receiving groups, theplurality of driving circuits respectively comprise a pulse signal inputend, pulse signal input ends of driving circuits corresponding to thereceiving electrodes in a same receiving group are electricallyconnected to a same pulse signal input line, the pulse signal input endsof driving circuits corresponding to the receiving electrodes indifferent receiving groups are electrically connected to different pulsesignal input lines.
 2. The ultrasonic recognition module according toclaim 1, wherein the receiving electrodes in a same row are located in asame receiving group, and the receiving electrodes in different rows arelocated in different receiving groups.
 3. The ultrasonic recognitionmodule according to claim 1, wherein the receiving electrodes in a samecolumn are located in a same receiving group, and the receivingelectrodes in different columns are located in different receivinggroups.
 4. The ultrasonic recognition module according to claim 1,wherein the plurality of driving circuits respectively comprise a diode,a first switch transistor, a second switch transistor, and a thirdswitch transistor; wherein, a first end of the diode is electricallyconnected to a receiving electrode, and a second end of the diode iselectrically connected to the pulse signal input end; a gates of thefirst switch transistor is electrically connected to a reset signal end,a first pole of the first switch transistor is electrically connected tothe receiving electrode, and a second pole of the first switchtransistor is electrically connected to the pulse signal input end; anda gate of the second switch transistor is electrically connected to thereceiving electrode, a first pole of the second switch transistor iselectrically connected to a power supply end, and a second pole of thesecond switch transistor is connected to a first pole of the thirdswitch transistor, a gate of the third switch transistor is electricallyconnected to a scanning signal end, and a second pole of the thirdswitch transistor is electrically connected to a signal reading end. 5.The ultrasonic recognition module according to claim 1, wherein thedriving circuits respectively comprise a storage capacitor, a firstswitch transistor, a second switch transistor, and a third switchtransistor; wherein, a first end of the storage capacitor iselectrically connected to the receiving electrode, and a second ends ofthe storage capacitor is grounded; a gate of the first switch transistoris electrically connected to a reset signal end, a first pole of thefirst switch transistor is electrically connected to the receivingelectrode, and a second pole of the first switch transistor iselectrically connected to the pulse signal input end; and a gate of thesecond switch transistor is electrically connected to the receivingelectrode, a first pole of the second switch transistor is electricallyconnected to a power supply end, a second pole of the second switchtransistor is electrically connected to a first pole of the third switchtransistor, a gate of the third switch transistor is electricallyconnected to a scanning signal end, and a second pole of the thirdswitch transistor is electrically connected to a signal reading end. 6.The ultrasonic recognition module according to claim 1, furthercomprising: a driving electrode disposed opposite to a film layer wherethe plurality of receiving electrodes are located, and a piezoelectriclayer located between the driving electrode and the film layer where theplurality of receiving electrode is located, wherein the drivingelectrode and the piezoelectric layer are formed over an entire surface.7. A display device, comprising the ultrasonic recognition moduleaccording to claim
 1. 8. The display device according to claim 7,wherein the receiving electrodes in a same row are located in a samereceiving group, and the receiving electrodes in different rows arelocated in different receiving groups.
 9. The display device accordingto claim 7, wherein the receiving electrodes in a same column arelocated in a same receiving group, and the receiving electrodes indifferent columns are located in different receiving groups.
 10. Thedisplay device according to claim 7, wherein the plurality of drivingcircuits respectively comprise a diode, a first switch transistor, asecond switch transistor, and a third switch transistor; wherein, afirst end of the diode is electrically connected to a receivingelectrode, and a second end of the diode is electrically connected tothe pulse signal input end; a gates of the first switch transistor iselectrically connected to a reset signal end, a first pole of the firstswitch transistor is electrically connected to the receiving electrode,and a second pole of the first switch transistor is electricallyconnected to the pulse signal input end; and a gate of the second switchtransistor is electrically connected to the receiving electrode, a firstpole of the second switch transistor is electrically connected to apower supply end, and a second pole of the second switch transistor isconnected to a first pole of the third switch transistor, a gate of thethird switch transistor is electrically connected to a scanning signalend, and a second pole of the third switch transistor is electricallyconnected to a signal reading end.
 11. The display device according toclaim 7, wherein the driving circuits respectively comprise a storagecapacitor, a first switch transistor, a second switch transistor, and athird switch transistor; wherein, a first end of the storage capacitoris electrically connected to the receiving electrode, and a second endsof the storage capacitor is grounded; a gate of the first switchtransistor is electrically connected to a reset signal end, a first poleof the first switch transistor is electrically connected to thereceiving electrode, and a second pole of the first switch transistor iselectrically connected to the pulse signal input end; and a gate of thesecond switch transistor is electrically connected to the receivingelectrode, a first pole of the second switch transistor is electricallyconnected to a power supply end, a second pole of the second switchtransistor is electrically connected to a first pole of the third switchtransistor, a gate of the third switch transistor is electricallyconnected to a scanning signal end, and a second pole of the thirdswitch transistor is electrically connected to a signal reading end. 12.The display device according to claim 7, wherein the ultrasonicrecognition module further comprising: a driving electrode disposedopposite to a film layer where the plurality of receiving electrodes arelocated, and a piezoelectric layer located between the driving electrodeand the film layer where the plurality of receiving electrode islocated, wherein the driving electrode and the piezoelectric layer areformed over an entire surface.
 13. A driving method of the ultrasonicrecognition module according to claim 1, comprising: providing multipledetection points by the ultrasonic recognition module, wherein each ofthe multiple detection points corresponds to the plurality of receivinggroups, and one receiving group corresponds to only one detection point;and applying pulse signals to pulse signal input ends of the pluralityof receiving groups corresponding to a same detection point by using thepulse signal input lines, wherein time points for loading the pulsesignals by receiving groups that are at a same distance from thedetection point are same, and time points for loading the pulse signalsby receiving groups that are closer to the detection point are laterthan time points for loading the pulse signals by receiving groups thatare far from the detection point.
 14. The driving method of theultrasonic recognition module according to claim 13, wherein thereceiving electrodes located in a same row are a receiving group, or thereceiving electrodes located in a same column are a receiving group. 15.The driving method of the ultrasonic recognition module according toclaim 14, wherein simultaneously performing a ultrasonic detection ondetection points corresponding to the receiving groups which do notspatially cross.
 16. The driving method of the ultrasonic recognitionmodule according to claim 14, wherein sequentially perform a ultrasonicdetection is on detection points corresponding to the receiving groupswhich spatially cross.
 17. The driving method of the ultrasonicrecognition module according to claim 16, wherein the sequentiallyperforming the ultrasonic detection on the detection points, comprises:receiving electrodes of the plurality of receiving groups correspondingto other detection points are in a floating state in response to thatperforming the ultrasonic detection one detection point.
 18. The drivingmethod of the ultrasonic recognition module according to claim 14,wherein every two adjacent receiving groups correspond to differentdetection points, and the receiving groups corresponding to differentdetection points are alternately arranged.
 19. The driving method of theultrasonic recognition module according to claim 18, wherein eachdetection point corresponds to an odd number of receiving groups, and areceiving group in a center location of the odd number of receivinggroups is a first receiving group, receiving groups on both sides of thefirst receiving group are second receiving groups, the second receivinggroups are symmetrically arranged along the first receiving group, andthe detection point is located right above the first receiving group.